This invention relates generally to an optical printing apparatus of the type where an image for printing is focused on an photo-sensitive surface and more particularly to an optical printing apparatus having a liquid crystal display using a neumatic type liquid crystal material having dielectric anisotropy which is subject to inversion dependent on frequency so as to provide light valves. Light from the valves is directed to the photosensitive surface by means of self-focusing lens constructed with light-transmitting fibers. Heretofore, a laser printer has been used as an optical printing or copying apparatus for producing printed picture images of high quality. However, a laser printer has disadvantages in that it is powered by high voltage, utilizes dangerous laser beams, and is expensive to construct. Various apparatuses have been proposed to replace the laser printer, for example, an apparatus using light-emitting diodes and an apparatus with liquid crystals serving as an optical shutter, as described in Japanese Laid-open patent publication No. 55-6604 and U.S. Pat. No. 4,297,022. However, these concepts have not matured into marketable products and are impractical as the printing speed of the apparatus is too low for commercial application.
What is needed is an optical printing apparatus which provides high quality printing at high speed without the use of laser beams, and is inexpensive in construction relative to the performance levels achieved.